EFFECT OF HIGH PRESSURES ON THE INFRARED AND RED ATMOSPHERIC ABSORPTION BAND SYSTEMS OF OXYGEN

Abstract

Absorption intensities in the 0–0 and 1–0 bands of the infrared [Formula: see text] and the 0–0 band of the red [Formula: see text] band systems of oxygen were measured in the pure gas in the range 50 to 150 atm and in O 2 –N 2 , O 2 –A, and O 2 –He mixtures up to 3000 atm total pressure at 25 °C. The integrated absorption coefficient of each band is expressed as a power series in ρ O2 and ρ f , the Amagat densities of oxygen and the foreign gas, respectively. The coefficient of the linear term Aρ O2 is a measure of the intrinsic (magnetic dipole) absorption of the O 2 molecule; it is much greater in the red than in the infrared system. The quadratic term, Bρ O2 2 , gives the induced absorption in O 2 –O 2 pairs; B is about ten times greater in the infrared than in the red system. These results explain intensity anomalies which have been observed in condensed oxygen. Induction effects in O 2 –N 2 and O 2 –A pairs are much smaller than in O 2 –O 2 pairs, and scarcely observable in O 2 –He pairs. The significance of these results is discussed.